engineering recuitment GATE ECE 2023-24 Test Series Communication Systems Amplitude Modulation Conventional Amplitude Modulation
A modulating signal of frequency fm with amplitude Am is modulated with a carrier with frequency fc and amplitude Ac. The resultant AM wave is shown below:
What is the instantaneous amplitude of the envelope of the above wave (if amplitude sensitivity of the modulator is 1/Ac)
1
40 cos 2πfc t + 10 cos 2πfm t cos 2 πfc t
2
80 cos 2πfc t + 20 cos 2πfm t cos 2πfc t
3
\(50\left[ {1 + \frac{1}{4}\cos 2\pi {f_m}t} \right]\)
4
40 + 10 sin 2 πfm t